Ghassanids

The Ghassanids (473-636) were a Christian Arab people and nation who came from Ma'rib in southern Arabia. A client state of the Byzantine Empire, the Ghassanids fought alongside the Byzantines against the Rashidun Caliphate during the Islamic Conquests, but they were destroyed after the Battle of Yarmuk. Some joined the Muslims to honor their Arab identity, while some joined the Melkites in Syria or headed to Turkey.

History
In 473, chief Amorkesos acknowledged the Ghassanids' status as foederati under the Byzantine Empire. Their capital was Jabiyah in the Golan Heights, and the Ghassanids provided a buffer zone against the Lakhmids, an Arab Christian "paradise on Earth" in southern Iraq that were aggressive against the Byzantines, and the Sassanid Empire. The Ghassanids guarded trade routes, and provided auxilliary units for the Byzantines. In 636, they were conquered by the Rashidun Caliphate after the Battle of Yarmuk, and some joined the Muslim Arabs to honor their Arab identity, while some also headed to Syria and Turkey, becoming Melkites and mixing with the Greeks.